If you are not satisfied with the ostomy nurses recommendations, you may need to move on to a dermatologist to get treatment. Just a thought. I have psoriasis and sometimes have to battle spots around the wafer like you, cutting away the tape where the area is affected. Hang in there.
Diagnosed with CD in 1979, many resections and meds
Perm Ileostomy July 1984 at Cleveland Clinic
Disease free since surgery